revion topic 14

Question 1

what is an ion

Answer 1

a charged atom

Question 2

what are insulators

Answer 2

they are substances that can’t conduct electricity

Question 3

what happens if you rub polythene rod on dry clothes

Answer 3

electrons would move from the surface of the clothes to the rod making them negatively charged

Question 4

what happens if you rub perspex rod on dry clothes

Answer 4

electrons would move from the rod to the surface of the clothes making the rod positively charged

Question 5

like charges?

Answer 5

repel

Question 6

unlike charges?

Answer 6

attract

Question 7

what is the function of the cell

Answer 7

it pushes the electrons around a complete circuit

Question 8

what is the function of a switch

Answer 8

it enables the current to be switched on or off

Question 9

what is the function of the indicator

Answer 9

its function is to emit light once a circuit is going through it

Question 10

what is the function of the diode

Answer 10

it allows the current trough only one direction

Question 11

what is the function of the light-emitting diode

Answer 11

does the same job as a normal diode but emits light when a current is passing through it

Question 12

what is the function of the ammeter

Answer 12

to measure the current of a circle

Question 13

what is the function of a fixed resistor

Answer 13

it limits the current in a circuit

Question 14

what is the function a variable resistor

Answer 14

allows the current to be varied

Question 15

what is the function of the fuse

Answer 15

it is designed to melt, breaking the circuit if the current passing thought it is greater than a certain amount

Question 16

what is the function of the heater

Answer 16

transfer electrical signal to heat the surroundings

Question 17

what is the function of the voltmeter

Answer 17

it is used to measure the potential difference

Question 18

what is an electrical current

Answer 18

it is the flow of charge

Question 19

what is the size of an electric current

Answer 19

it is the rate of following of electrical charge

Question 20

what happens when you turn torch on

Answer 20

millions of currents would pass through the torch and the lamp every second, as then electrons would pass through the filament since it made of electrons, them electrons would transfer energy from the cell to the touch

Question 21

what is electrical charge is measured in

Answer 21

coulombs (C)

Question 22

electrical current is measured in

Answer 22

amperes (A)

Question 23

current =

Answer 23

charge flow/time taken

Question 24

what happens if an ammeter is in series with the lamp?

Answer 24

the same amount of current would pass through them

Question 25

what is the potential difference

Answer 25

it is the energy transferred to the lamp

Question 26

what happens if the voltmeter is connected parallel to the torch lamp

Answer 26

it would measure the potential difference across it

Question 27

potenial diffrence across a componetent=

Answer 27

energy transferred/charge

Question 28

resistance =

Answer 28

pontentail difference/current

Question 29

what is the unit of resistance

Answer 29

ohms

Question 30

what does the ohms law state

Answer 30

that a current through a resistor at constant temperature is directly proportional to the potential difference across the resistor, the wire would be known as an ohmic conductor

Question 31

what will happen in a current-potential difference graph in filament light

Answer 31

it is not directly proportional because the line would cure towards the end because as the current increases the resistance increases, so as the filament lamp temperature increase the resistance would, and this is because the ions in the filament light would stay vibrating faster making it harder for the electrons to pass through, reversing the potential difference won't change anything

Question 32

what will happen in a current-potential difference graph in the diode

Answer 32

the diode isn't an ohmic conductor since it would curve toward the y-axis in a forward direction, and if you reverse the direction the current would be virtually zero so there would be a higher distance in the reverse direction

Question 33

what will happen in a current-potential difference graph in thermistor

Answer 33

it is an ohmic conductor, and as the temperature increases its resistance decreases

Question 34

what will happen in a current-potential difference graph in LDR

Answer 34

it is an ohmic conductor, and if the brightness of the light is increased them the resistance would decrease

Question 35

what happens to a current in a series circuit

Answer 35

the current would pass through each component

Question 36

what happens to the potential difference in a series circuit

Answer 36

the total potential difference of voltage supplied is shared between each component

Question 37

what happens to the potential difference if there was more than one cell in a series circuit

Answer 37

the total potential difference of cells in a series is the sum of the potential difference of each cell

Question 38

what happens to resistance in a series circuit

Answer 38

the total resistance of components in a series is equal to sum of the resistance in each component

Question 39

what happens to the current in a parallel circuit

Answer 39

the total current through the whole circuit is the sum of the currents through the separate components

Question 40

what happens to the potential difference in a parallel circuit

Answer 40

the potential difference across each component is the same

Question 41

the bigger the resistance in a component in a parallel circuit

Answer 41

the smaller the current is, as it can be represented as | current = potential difference/ resistance

Question 42

what is a sensor circuit

Answer 42

it is a circuit made up of two or more resistors in a circuit connected to a source of fixed p.d, where the fixed p.d is shared between the two resistors

Question 43

what does a temperature sensor include

Answer 43

thermistor

Question 44

what happens if you increase the temperature in a temperature sensor

Answer 44

the resistance would decrease so the battery shared p.d decreases as well

Question 45

what does a light sensor include

Answer 45

an LDR

Question 46

what happens if you increase the brightness in a light sensor

Answer 46

the resistance would decrease so the shared battery p.d decreases as well, because of this the share of battery p.d across resistor increases

Question 47

what is a rely

Answer 47

it is an electrical operant switch used in electrical circuits to switch machines on and off

Question 48

how does a temperature operant alarm work

Answer 48

so if the thermistor is cold there won't be enough resistance to turn on the buzzer, so when you increase the temperature of the thermistor there would be enough temperature to turn the busser

Question 49

what happens if a resistor is which out in a sensor to a variable resistor

Answer 49

when the temperature increase the resistance would increase